In order to improve fuel economy of modern gas turbine engines, it is often desirable that the compressor delivery temperature be relatively very high. However, these high compressor delivery temperatures produce even greater thermal gradients between the inner and outer portions of the impellers than in older engines, which correspondingly induce greater thermal stresses in the impellers and have an impact on their low-cycle fatigue (LCF) life.
Accordingly, there is a need to provide a way of mitigating the thermal gradients in centrifugal impellers of gas turbine engines.